The present invention relates to a method of making a unitary construction element having a thermal barrier or break therein, commonly referred to as a thermal barrier extrusion, which can be employed in construction of windows, doors, frames therefor, and the like.
The invention generally relates to a method of making a thermobreak member or thermal barrier metal extrusion utilizing a single metal extrusion and a plastic, or the like, insulating member.
The invention especially relates to a method of making a unitary thermal barrier extrusion wherein mechanical means are employed to join an insulating member with a metal extrusion or shape.
A variety of types of thermal barrier constructions and methods therefore have been developed. U.S. Pat. Nos. 3,204,324; 3,393,487; 3,411,254; 3,420,026; 3,517,472; 3,815,216; and 3,823,524 and Swiss Pat. No. 320,998 (same as British Pat. No. 768,499) are illustrative of these.
U.S. Pat. No. 3,204,324 is representative of a method of making a thermal barrier construction element or insulating construction, wherein a metal shape having a generally U-shaped channel therein is filled with a flowing resinous insulating composition; the composition is cured, and subsequently a portion of the metal member or web forming the base of the channel is removed. U.S. Pat. No. 3,823,524 relates to a similar method but employs a web member which extends convexly between the structural member forming the channel. Both of these methods require the use of a liquid resinous composition which is subsequently cured or hardened.
U.S. Pat. No. 3,393,487 discloses a somewhat more complicated process for making a thermal insulating joint construction and also utilizes a liquid plastic material. In such process, two separate elongated metal shapes are spaced apart and fastened together with a solid first insulating member. The two shapes and the first insulating member provide a channel in which a second thermal insulating member is flowed therein. Upon solidification of the latter, the metal and insulating members are locked together as an integral unit. U.S. Pat. No. 3,411,254 provides for another type of plastic thermobreak which utilizes a plastic locking strip which contains a heat actuated blowing agent to join two separate metal shapes. After assembly of the two metal shapes and the plastic strip, the unit is heated to expand the plastic into tight engagement with the two metal members.
U.S. Pat. No. 3,420,026 discloses several types of thermal insulating members and methods of making them. In one type, two separate metal members are mechanically joined to a central insulating member by crimping or deformation of groove means or projections on the metal members. In one particular type of thermal break construction, the insulating member is in the shape of a Maltese cross in cross-section. In another embodiment, the insulating member is made from a thermoplastic material and a portion thereof is heated to cause melting and flow of the plastic into an associated groove means formed by the two metal members. Upon cooling of the plastic, the metal and plastic member are unitarily joined together. U.S. Pat. No. 3,517,472 also illustrates a mechanical joining process similar to that of the former and additionally represents the use of a plastic or insulating member which expands upon heating.
U.S. Pat. No. 3,815,216 illustrates still another method of manufacturing a thermal break construction element and employs a metal extrusion which has a removable interior section which is subsequently removed to separate the extrusion into two metal members. While maintaining the separate metal members spaced apart, a plastic material is inserted therebetween. The construction element can be made in a continuous operation.
The Swiss patent (or British patent) discloses several types of window or door frames, one of which employs a crimp system using two separate metal extrusions having a pair of flanges thereon which form grooves for receiving a plastic rod. After the rod or thermal barrier member is introduced into the grooves, the flanges are pressed towards the plastic rod or crimped thereon so that they are flush with the sides of the rod.
In currently manufacturing thermal barrier extrusions employing a crimp or stitching system, rollers are normally used to provide crimping of the metal flanges on the insulating or plastic member. Conventionally, two rollers or wheels are required to crimp the flanges. One roller must actually bend the metal flanges on the insulating member while the other roller must back-up or hold the metal extrusion in the correct position for joining metal and plastic members. To accomplish the crimping action, clear access must be available on both sides of the plastic member on which crimping of the metal members occurs. In some cases, a small wheel or support is laterally employed to serve as a back-up. The size of the support and the forces required to obtain a tight joint create a number of operating problems. The types of shapes or extrusions which can be used in this method are limited.
The present invention has a number of advantages over these prior art constructions. The invention eliminates the necessity of using two or more separate metal shapes or pieces and eliminates the handling of multiple pieces through normal finishing operations such as painting, anodizing, and other manufacturing and assembly steps. The invention also dispenses with the need for liquid or expandable plastic materials which are difficult to handle and require special equipment.
It is a primary object of the instant invention to provide a crimp system or method of making thermal barrier extrusions which overcomes the disadvantages of prior art systems and which can be used with a wide variety of metal shapes or extrusions.
Another object of the invention is to provide a crimp or stitching system for making thermal barrier construction elements or members wherein a single extrusion is employed.
Other objects and advantages of the present invention will become more readily apparent from a consideration of the description and drawings hereinafter.